package org.seckill.service.impl;

import org.seckill.dao.SeckillDao;
import org.seckill.dao.SuccessKilledDao;
import org.seckill.dao.cache.RedisDao;
import org.seckill.dto.Exposer;
import org.seckill.dto.SeckillExecution;
import org.seckill.entity.Seckill;
import org.seckill.entity.SuccessKilled;
import org.seckill.enums.SeckillStateEnum;
import org.seckill.exception.RepeatKillException;
import org.seckill.exception.SeckillCloseException;
import org.seckill.exception.SeckillException;
import org.seckill.service.SeckillService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.DigestUtils;

import java.util.Date;
import java.util.List;

/**
 * SeckillService接口
 * Created by dong on 16-6-13.
 */
//@Component @Service @Dao @Controller
@Service
public class SeckillServiceImpl implements SeckillService {

    private Logger logger = LoggerFactory.getLogger(this.getClass());
    //注入Service依赖
    @Autowired
    private SeckillDao seckillDao;
    @Autowired
    private SuccessKilledDao successKilledDao;

    @Autowired
    private RedisDao redisDao;

    //md5盐值字符串，用于混淆MD5
    private final String slat = "dasfasdf3w25ads@#$*dfdsafsadf%#$%#@%";

    @Override
    public List<Seckill> getSeckillList() {
        return seckillDao.queryAll(0, 4);
    }

    @Override
    public Seckill getById(long seckillId) {
        return seckillDao.queryById(seckillId);
    }

    @Override
    public Exposer exportSeckillUrl(long seckillId) {
        //优化点:缓存优化 :超时的基础上维护一致性
        //1、访问redis
        Seckill seckill = redisDao.getSeckill(seckillId);
        if (seckill == null) {
            //2:访问数据库
            seckill = seckillDao.queryById(seckillId);
            if (null == seckill) {
                return new Exposer(false, seckillId);
            } else {
                //3:放入redis
                redisDao.putSeckill(seckill);
            }
        }


        Date startTime = seckill.getStartTime();
        Date endTime = seckill.getEndTime();
        //系统当前时间
        Date nowTime = new Date();
        if (nowTime.getTime() < startTime.getTime()
                || nowTime.getTime() > endTime.getTime()) {
            return new Exposer(false, seckillId, endTime.getTime(), startTime.getTime(), nowTime.getTime());
        }
        //转化特定字符串的过程,不可逆
        String md5 = getMD5(seckillId);
        return new Exposer(true, md5, seckillId);
    }

    /**
     * 生成MD5加密字符串
     */
    private String getMD5(long seckillId) {
        String base = seckillId + "/" + slat;
        return DigestUtils.md5DigestAsHex(base.getBytes());
    }

    @Override
    @Transactional
    /**
     *  使用注解控制事物方法的优点:
     *  1: 开发团队达成一致约定,明确标注事物方法的编程风格.
     *  2: 保证事物方法的执行时间尽可能短,不要穿插其它网络操作,RPC/HTTP请求/或者剥离到事物方法外部
     *  3: 不是所有的方法都需要事物,如只有一条修改操作, 只读操作不需要事物控制
     */
    public SeckillExecution executeSeckill(long seckillId, long userPhone, String md5) throws SeckillException {
        if (md5 == null || !md5.equals(getMD5(seckillId))) {
            throw new SeckillException("seckill data rewrite");
        }
        //执行秒杀逻辑: 减库存 + 记录购买行为
        Date nowTime = new Date();
        try {
            //记录购买行为
            int insertCount = successKilledDao.insertSuccessKilled(seckillId, userPhone);
            //唯一: seckillId,userPhone
            if (insertCount <= 0) {
                //重复秒杀
                throw new RepeatKillException("seckill repeated");
            } else {
                //减库存,热点商品竞争
                int updateCount = seckillDao.reduceNumber(seckillId, nowTime);
                if (updateCount <= 0) {
                    //没有更新到记录,秒杀结束 rollback
                    throw new SeckillCloseException("seckill closed");
                } else {
                    //秒杀成功 commit
                    SuccessKilled successKilled = successKilledDao.queryByIdWithSeckill(seckillId, userPhone);
                    return new SeckillExecution(seckillId, SeckillStateEnum.SUCCESS, successKilled);
                }

            }

        } catch (SeckillCloseException e1) {
            throw e1;
        } catch (RepeatKillException e2) {
            throw e2;
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
            //所有编译期异常 转化为运行期异常
            throw new SeckillException("seckill inner error:" + e.getMessage());
        }
    }
}
